Need to add differential Fluid?
Thread Starter
Racer
Joined: Mar 2005
Posts: 285
Likes: 0
From: Keller Texas
Need to add differential Fluid?
Need to add to differential fluid. I pulled the vent cap but what size hose will fit in there. (79 Corvette). Where would I find this hose. I do have a Mity Vac. Not the fancy one.
Thanks
Thanks
Safety Car
Joined: Oct 2000
Posts: 3,547
Likes: 12
From: Carbondale Pa.
Maybe I aint understanding you but if you add fluid thru the vent cap how to you expect to check the fluid level on the rear ? Pretty sure it needs to be added thru the filler plug. Peace,,,Moosie 
Instructor
Joined: Nov 2007
Posts: 156
Likes: 1
From: Edgewood Kentucky
There is no drain hole on a 79 unless you drill one in the bottom. How do you know you need fluid if you didn't take the side plug out? When I changed my 79 fluid a couple months ago, I used a vac to suck old fluid out then used GM additive and fluid. The dealer gave me a little hose that fit on the jugs of fluid. Still a little messy. When fluid starts to run out hole, its full. Made a big difference in mine.
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Safety Car
Joined: Jun 2004
Posts: 4,652
Likes: 80
From: Lakeland Florida
I changed the diff fluid on my 72 and 75. The rear end looked the same on both cars, so it may be the same on the 78. The plug is a square bolt that goes into the diff unit. Once you take that out, you can drain the old fluid by inserting a tube, and sucking out the fluid with a pump that you can buy at your local parts store ( approx. $10).
After the old fluid is out, I put in the 4oz. differential additive first, then put in the gear oil. If you are in the area to check the fluid, or to top it off , why not just put in all new gear oil and know that it is new, and when it was replaced.
kdf
After the old fluid is out, I put in the 4oz. differential additive first, then put in the gear oil. If you are in the area to check the fluid, or to top it off , why not just put in all new gear oil and know that it is new, and when it was replaced.
kdf
